Safety interlock for the firing mechanism of a cannon



uly 17, 1962 H. J. REEPMEYER 3,044,364

SAFETY INTERLOCK FOR THE FIRING MECHANISM OF A CANNON Filed Sept. 21.1960 5 Sheets-Sheet 1 INVENTOR.

H IHTELHIREE THE ET BY E P y July 17, 1962 H. J. REEPMEYER 3,044,364

SAFETY INTERLOCK FOR THE FIRING MECHANISM OF A CANNON Filed Sept. 21.1960 5 Sheets-Sheet 2 IN VEN TOR.

BYH LUII-IREEPIHEYET 1 1. 73%;. v QJW July 17, 1962 H. J. REEPMEYER3,044,364

I SAFETY INTERLOCK FOR THE FIRING MECHANISM OF A CANNON Filed Sept. 21.1960 5 Sheets-Sheet 3 IN V EN TOR.

July 17, 1962 H. J. REEPMEY'ER 3,044,364

SAFETY INTERLOCK FOR THE FIRING MECHANISM OF A CANNON Filed Sept. 21,1960 5 Sheets-Sheet 4 4s 72 1 70 I 7a FigZZ 62 7 116 FIQEL INVENTOR.

HEImllII 1.1.H E EPTHEYEI WHZMQ July 17, 1962 H. J. REEPMEYER 3,

SAFETY INTERLOCK FOR THE FIRING MECHANISM OF A CANNON Filed Sept. 21.1960 5 Sheets-Sheet 5 INVENTOR. H ETTHELH lREE BY PIIIE'YET 1. 0. mm; 9PQ4 QM i 3,044,364 SAFETY INTERLUCK FOR TI-E FIRIN MECHANISM OF A. CANNONHerman J. Reepmeyer, Cohoes, N.Y., assignor to the United States ofAmerica as represented by the Secretary of the Army Filed Sept. 21,1960, Ser. No. 57,589

Claims. (Cl. 8927) (Granted under Title 35, US. Code (1952), sec.266)

The invention described herein may be manufactured.

, operating mechanisms, and particularly the firing mechanisms, of theguns.

In the large caliber guns of cannon types wherein the projectile andbagged propellant are loaded separately into the firing chamber by handand the primer is loaded in the firing mechanism located in thebreechblock, the conventional means for preventing accidental dischargeof the chambered round before the breech is closed and locked is to havethe'primer retained by a firing lock which is installed by manualthreading into the breechblock only after the breechblock is closed andlocked. When the firing lock is installed in the breechblock, a safetyplunger is forced laterally into engagement with a locking slot in thecrankshaft employed to actuate the breechblock and thereby preventsdisplacement thereof from the closed position.

With tlus device, each time the cannon is fired the lock must bemanually removed before the breech can be opened and the firing lockwith a live primer must be reinstalled before the cannon can be firedagain. This, while providing positive safety, is a two-stage, timeconsuming operation and should the firing lock jam considerably time islost in the disassembly of the safety plunger and firing lock before thebreech can be opened.

Therefore, to increase the rate of fire of such cannous, there has beendevised a firing mechanism which includes a percussion device which ishingedly mounted on the b-reechmechanism and which is biased to an openposition by a cooperating spring. The percussion device States Patent isreleasably held in the closed position, ready for firing by a latchwhich, when actuated, permits the percussion device to be swung to theopen position by the cooperating spring. With the opening of thepercussion device, an extractor is triggered to eject the case of thespent primer from the breech mechanism.

It is the principal object of this invention to provide for cannonsusing such hinged percussion devices a safety plunger. which isoperationally disposed in the breech mechanism between the latch of thepercussion device and the breechblock actuating crankshaft and isenergized therewith so. that, when the crankshaft is rotated fordisplacement of the breechblock from the closed position, the safetyplunger is actuated against the latch for release of the percussiondevice. Whereby, the percussion device is swung clear of the primer, soas not to be actuatable thereagainst, or clear of the spent primer case,as the case may be, and the primer or spent case is, therefore, automatically ejected from the breechblock.

It is another object of this invention to provide such a safety devicewherein the plunger is actuated by a cam tion.

1&3

slot formed in the crankshaft and such cam slot is generated so that theplunger is actuated against the latch during the initial rotation of thecrankshaft. Whereby, a live primer may be automatically ejected from thepercussion device by rotation of the crankshaft while the chamberedcartridge is sufiiciently supported by the breechblock to prevent anydamage if the chambered cartridge should be accidentally dischargedbefore ejection of the primer.

It is still another object of this invention to provide for cannons ofstated type a safety device whichis simple and rugged in construction,easy to manufacture and positive in operation.

The specificnature of the invention as well as other objects andadvantages thereof will clearly appear from a description of a preferredembodiment as shown in the accompanying drawings in which:

FIG. 1 is a view of die rear end of a cannon with the safety interlockof this invention installed therein;

FIG. 2 is a View taken along line 2-2 of FIG. 1;

FIG. 3 is a fragmentary view similar to FIG. 2 but showing thepercussion device unlatched and free to be swung to the open position;

FIG. 4 is a view. taken along line, 4-4 of FIG. 2;

FIG. 5 is a view taken along line 55 of FIG. 3;

FIG. 6 is a view similar to FIGS. 4 and Sbut showing the percussiondevice swung to. the open position;

7 FIG. 7 is a viewtaken along line 7--7 of FIG. 6;

FIG. 8 is a view similar to FIG. 7 but showing the relationship of thepercussion device and extractor for chambering a primer in the receiverof the firing mecham sm; V

FIG. 9 is a perspective exploded view of the crank mechanism forrotating the breechblock; and

FIG. 10 is a perspective exploded viewof the carrier and plungen V iShown in the figures is a cannon, such as the. 15 5-MM Gun M2, having atube 14. with a breech ring 15 fixed to therear end thereof and achamber 16 which is closed by a breech mechanism 18. Breech mechanism 18includes a breechblock 20 rotatingly supported by a carrier 22 which ispivotally mounted on breech ring 15 by means of a vertically disposedhinge pin 24 so that the breech mechanism may be swung in a horizontalplane between an open and a closed position. 7

Breechblock 20 is mounted on carrier 22 by means of 'a cylindricalspindle 25 which extends from the carrier '7 at right angles thereto soas to be received by a mating bore 26 extending axially through thebreechblock. Provided around the periphery of breechblock 20 areinterrupted threads 28 which are. arranged to pass through cooperatinginterruptedthreads 30 inside of breech ring 15-when the breechblock isactuated to the closed posi- 'tion, so as to be disposed in back of suchbreech ring threads when the breechblock is rotated to the lock posi-Complete locking is achieved when breechblock 20 is rotated 35 from theunlocked to the locked position.

Rotation of breechblock 20 is achieved by a crankshaft '32 which ismounted in carrier 22 for 135 rotation.

Crankshaft 32 is provided at one end with a crank 34 which includes acylindrical riser portion 36 formed integrallyon the crankshaft and arod 38 which extends from the riser portion so as to be spaced radiallyfrom the longitudinal axis of the crankshaft and disposed parallelthereto. A cylindrical crosshead 40 is provided with a diametrical hole41 therethrough for receiving rod 38 and such crosshead is slidinglyreceived by a mating semicylindrical recess 42 in breechblock 20 sothat, as rod 38 is displaced eccentrically by rotation of crankshaft 32,

the breechblock is rotatingly displaced on spindle 25. Crank 34 isdesigned so as to convert the rotation V of crankshaft 32 to the 35rotation of breechblock 20 required for actuation thereof between thelock and unlock positions.

Crankshaft 32 is manually actuated by a handle 44 which is fixed to thecrankshaft at the outer end thereof. Whereby, when handle 44 is swungdownwardly from a vertical to a horizontal position, breechblock 20 isrotated to the unlock position and then, when the handle is pushedforwardly relative to the direction of cannon 12, for angulardisplacement in a horizontal plane, breech mechanism 18 is swung to theopen position. Breechblock 20 is closed and locked through a reversal ofthe above-mentioned movements.

Brech mechanism 18 carries a firing mechanism 46 which includes areceiver 48 for chambering a primer 50 and such receiver is received byan axial bore 52 which extends axially through spindle 25 so thatdischarge of the primer in the receiver will in turn cause discharge ofthe round chambered in tube 14 when the breechblock is closed toregister the primer with the propellant in the tube. Primer 50 isdischarged by a percussion device 54 which includes a cylindricalhousing 56 in which there is contained a spring-loaded firing pin 58disposed for discharge of the primer. Housing 56 includes a flange 62which'projects from the forward edge thereof and by means of which thehousing is mounted on a shaft 64 extending outwardly from the rear faceof carrier 22. Housing 56 is disposed on shaft 64 for pivotaldisplacement between a closed position wherein the rear end of receiver48 is blocked to support the discharge of primer 50 and firing pin 58 isin alignment therewith, and an open position wherein the rear end of thereceiver is cleared for the installation of the primer and ejection ofthe fired case thereof. Shaft 64 is arranged to be rotatable in receiver48 and to extend outwardly beyond flange 62 so that a lever 66 may bemounted on the extending end for turning the shaft.

Percussion device 54 is biased to the open position by a helical torsionspring 68 which is operationally interposed between flange 62 andreceiver 48 and is releasably secured in the closed position by a slide70 which is mounted laterally through the housing, respective to thelongitudinal axis thereof, and flange 62. One end of slide 70 isprovided with an aperture 72 to permit extension of shaft '64therethrough and such aperture is notched, as noted at 74, for receivinga mating tang 76 extending radially from the shaft. Whereby, rotation ofshaft 64 by lever 66 is converted to translational movement of slide 70.The opposite end of slide 70 is receivable by a suitable recess 78 inreceiver 48 so that rotation of lever 66 in one direction will move suchopposite end, noted at 79, into the recess for securing percussiondevice 54 in the closed position. When lever 66 is rotated in theopposite direction, end 79 is retracted from the recess for release ofthe percussion device. Recess 78 extends through receiver 48 to theperimeter thereof to permit the end of slide 70 to be contacted foralternate displacement of the slide to release percussion device 54.

Slide 70 is contactable by a plunger 82 which is slidingly mounted incarrier 22 by means of a mating channel 84 formed in the rear facethereof so that the plunger is displaceable along the extendedlongitudinal axis of the slide. Plunger '82 includes a shank 86 which isof square cross-section and is terminated at one end by a probe '88 ofreduced cross-section so as to be insertable into recess 78 for contactwith end 79' of slide 70. Plunger 82 is actuated manually by a handle 90which includes a fingerpiece 92, an integral cylindrical portion 94which is receivable as by press fit in a hole 96 through shank 86, and acylindrical cam follower 98 which extends axially from the cylindricalportion. Handle 90 is secured to shank 86 by a pin 102. Thus, whenplunger 82 is installed in channel 84, fingerpiece 92 extends outwardlytherefrom, cam follower 98 extends inwardly for cooperation with a campath 100 formed in crankshaft 32, as here- 4 inafter described, andprobe 88 is positioned for movement against end 79 of slide 70.

Plunger 82 is slidingly retained in channel 84 through the engagement oftwo pairs of lugs 104, which extend vertically from shank 86 in spacedrelationship therealong, with cooperating slots 105 in the channel.Clearances 106 are provided for the insertion of the lugs 104 into slots105. A compressible coil spring 108 is disposed between plunger 82andthe right-hand end of channel 84 for biasing the plunger to the lefttowards slide and position the lugs 184 away from the clearances 106 sothat the plunger is retained within the channel.

Cam path is formed around riser portion 36 of crank 34 and is generatedso that when crankshaft 32 is rotated to rotate breechblock 20 from thelock to the unlock position, plunger 82 is actuated by the cam pathagainst slide 70 to push end 79Lthereof from recess 78 for release ofpercussion device 54. Cam path 100 is generated, as shown at A in FIG.9, so that slide 70 is actuated out of recess 78 during the first 8 ofrotation of breechblock 20 whereby the breechblock is fully supportedinevent a round in chamber 16 is accidentally discharged by percussiondevice 54 before it is swung open to move primer 50 clear of thepropellant in the chamber.

Cam path 100 is also generated to dwell for approximately 72, as notedat B, and then is generated, as noted at C, to approximately 102 to moveplunger 82 further to the left (facing the breech end of tube 14) towhere probe 88 will be positioned to block any accidental displacementof percussion device 54 to the closed position thereof wherein primer 50might be accidentally discharged as the propellant is passed therebyinto chamber 16.

An extractor 112 is pivotally mounted in receiver 48 by means of a pin114 so as to extend upwardly in a mating clearance in the rear face ofhousing 56 to engage the front of the rim of primer 50. Provided on therear side of extractor 112 below pin 114 is an arcuate protuberance 116which is contactable by a cam 118 on the front face of housing 56, whenpercussion device 54 swings from the closed position, to pivot the upperend of the extractor outwardly for ejection of the fired case of primer50 or the live primer when the cannon is to be cleared.

Thus, when the cannon has been fired or is to be cleared, handle 44 ispulled downwardly causing rotation of crankshaft 32 and, consequently,crank 34 whereby breechblock 20 is rotated from the lock position. Atthe same time, cam path 100 is rotated along cam follower 98 of plunger82 so that the plunger is actuated against slide 70 during the initialrotation of crankshaft 32 and while threads 28 on breechblock 20 arestill engaged with threads 30 in breech ring 15. Whereupon, when end 79of slide 70 is pushed clear of recess 78, percussion device 54 is freeto be swung open under the bias of spring 68. As percussion device 54swings to the open position, cam 118 thereon contacts arcuateprotuberance 116 on extractor 112 to eject the fired case of primer'50or the live primer if the cannon is to be cleared after being readiedfor fire. Consequently, cannon 12 is made safe when breechblock 20 isunlocked as primer 50 is removed from firing mechanism 46.

To load the cannon with breech mechanism 18 swung open, a projectile andbagged propellant are pushed into chamber 16 of tube 14 and then handle44 is pulled rearwardly to close the breech mechanism. When breechmechanism 18 is closed, handle 44 is pushed from a horizontal to avertical position which causes rotation of breechblock 20 to the lockposition. Primer 50 is then chambered in receiver 48 and lever 66rotated to swing percussion device 54 upwardly to the closed position.As lever 66 is rotated, shaft 64 is rotated therewith to actuate slide70 laterally through the cooperation of tang 76 with notch 74 to moveend 79 of the slide into recess 78 for securing percussion device 54 inthe closed position. As slide 70 is actuated to the latch position bylever 66, end

'79 of the slide pushes plunger 82 to the right to move cam follower 98thereon into contact with cam path 100 and ready to unlatch thepercussion device 54 for'autornatic ejection of primer 50 or the spentcase thereof when handle 44 is pulled downwardly.

From the foregoing it is clearly evidentthat there is provided hereinfor cannons a safety device which is easy to manufacture, simple andrugged in construction and positive in operation. a

Although a particular embodiment of the invention has been described indetail herein, it is evident that many Variations may be devised withinthe spirit and scope thereof and the following claims are intended toinclude such variations.

I claim:

1. In a cannon having atube, a breech ring mounted thereon, andabreechblock mounted for rotation "on a spindle of a carrier mounted onthe breech ring for pivotal displacement between an open and a closedposition, a

- crankshaft rotatingly mounted in the carrier, a crank disposed on oneend of said crankshaft for operational cooperation with the breechblockfor converting eccentric displacement of said crank by rotation of saidcrankshaft to rotation of said breechblock for alternatedisplacementbetween a lock and an unlock position, a firing mechanism including areceiver disposed in the spindle for chambering a primer and apercussion device mounted on said receiver for pivotal movement betweena closed position in back of the primer chambered in said receiver andan open position, a spring operationally disposed betweensaid receiverand said percussion device for biasingsaid percussion device to the openposition, a slide disposed in said percussion device for releasablysecuring said per end of said slide for actuation thereof to unlock saidpercussion device from saidreceiver, and including-cooperating cam meanson said crank and said plunger for converting rotation of "saidcrankshaft in a direction for moving the breechblock to an unlockposition to translational movement of said plunger against said slidefor actuation thereof to unlock said percussion device.

4. The cannon as defined in claim 1 wherein the breech ring is providedwith internal threads ofinterrupted type and the breechblock is providedwith external threads of similar type arranged for displacement in backof the internal threads of the breech ring for securing the breechblockagainst displacement relative thereto, and including a cam followerextending from said plunger to said crank, and a cam path formed on saidcrank for cooperation with said cam follower for converting rotation ofsaid crank to translational displacement of said plunger, said cam pathbeing generated so as to actuate said plunger for release of saidpercussion device when said crank is rotatedto rotate the breechblock totheunlock position and to completely release said percussion devicebefore the threads'ofthe breechblock are clear of the threads inthebreench ring.

5. The cannon as defined in claim 1 wherein said extendinglongitudinally from one end, a handle includv ing a cylindrical portionwith'a finger portion and a cam follower disposed on the opposite endthereof, said handle being mounted through said plunger so that said camfollowerand said finger portion extend fromjopposite cussion device totheca'rrier in the closed position, and a,

plunger operationally disposed between said'crankshaft and said slidefor transferring rotation of "said crankshaft to displacement of saidslide for actuation thereof" to recrank is provided with a cylindricalriserI portion and said slide is disposed for translationaldisplacementin said percussion device, and including a cam path formedin said riser portion, and acam follower extending from said plunger toengagesaid cam path, said cam follower being disposed for convertingrotation of said crankshaft to translational displacement of saidplunger. e

3. The cannon'as defined in claim 1 wherein saidslide and said plungerare disposed in longitudinal alignment and said plunger is disposed foractuation against one sides thereof, a channelformed in the rear face ofthe carrier for slidingly receiving said plunger, said channel beingdisposed for positioning said plunger so that said probe is actuatableagainst one end of said slide for actuationthereof to release saidpercussion devi ce, said ,fingerpiece extending outwardly from thecarrier and said cam follower extending tov said crank, and a cam pathformed on said crank so as to cooperate with said cam follower forconverting rotation of said crankshaft in a,

direction. to actuate the breechblock to theunlock position'totranslational displacementof said plunger to actuate said probe againstsaid slide for actuation thereof,"

to release said percussion device;

References Cited in the file of this patent v UNITED STATES PATENTSSummerbell et a1 Apr. 18, 1950 Oliver Sept. 27, 1949

